Won't go over 2000rpm

Asked by Guru6DY8 May 11, 2017 at 10:34 PM
about the 2004 GMC Sierra 1500

Question type: Maintenance & Repair

Won't go over 2000rpm or shift at 60mph when trying to accelerate or trying to pass a car.truck has a slight knocking noise or bumping noise when trying to do so. Then either holds at 60 and gradually goes faster at a slow rate or it will start to decelerate down as if it is in neutral​ or something. Doesn't happen all the time but is starting to happen more frequently. Any help is greatly appreciated

1 Answer

Could be a number of things, first I would have the fuel delivery system checked, fuel pump pressure, bleed down test, and also could be the fuel regulator. Should check the spark plugs to see how it is firing, see that the plugs are not wet or blacken up with carbon indicating a problem with the ignition system. The knock may be coming from the engine, all depends.

Recently I bought a 91 seirra GMC. The kid says it had a new transmission put into it recently that has a shift kit for towing, thus causing it to shift hard. drove it for like a week with no problems...

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